Electrical coil assembly



April 10, 1951 w M. DROBISH ETAL ELECTRICAL COIL ASSEMBLY Filed Oct. 10,1947 /NVNTO/?$ W M. flRoa/sw E. A DHOM W Patented Apr. 10, .1951

ELECTRICAL COIL .A-SSEIWBLY William 1M. Drobish, Oak Park, and Edwin L.Drom, Brookfield, 'Ill., assignors to Western Electric Company,Incorporated, New York, N. Y., a corporation of New York ApplicationOctober 10, 1947, SerialNo. 779,106

'10 Claims.

This invention relates to electrical coils and more particularly toloading .coilsforcommunication transmission lines.

An object of this invention is to provide a new and eflicient loading.unit for communication transmission lines.

In accordance with one embodiment of this invention a loading coilassembly is provided which comprises one or more toroidal loading coilsmounted on a dowel and spaced from each other by insulating andshielding washers. Each of the coils has associated therewith a terminalsupporting washer having stub terminals radiating therefrom to which areconnected the ends of the coil windings. A terminal supporting washer ofthis type is described more fully and claimed in the copendingapplication of E. L. Drom, Serial No. 717,527, filed December 20, 1946.To prevent short circuits between the terminals and the coils, aperforated insulating strip of paper or fiber is laid lengthwise acrossthe assemblage with the terminal stubs extending through theperforations. The assemblage is then encased by a cardboard tube, andthe entire assemblage is impregnated with an insulating varnish.

A complete understandingof the invention will be had by reference to thefollowing detailed description taken in conjunction with theaccompanying drawing, in which Fig. 1 is a view partly in elevation andpartlyin the assembled unit stripped of insulating com.-'

pound for better illustration;

Fig. 2 is a cross-sectional view of theassembly shown in Fig. 1 taken onthe line 2-2 of that figure;

Fig. 3 is an illustration of one way of preform.- ing the perforatedstrip before it is applied'to the loading coil;

Fig. 4 is a broken-away view partly in section illustrating the use ofan imperforate tape .instead of the perforated strip shown in Figs. 1, 2and 3; and

Fig. 5 is a cross-sectional view of the embodiment shown in Fig. 4 takenon the. lines 5-5 of that figure.

As will be seen in the drawings a loading coil assembly 28 may compriseaplurality of similar toroidal coils 2| mounted on a dowel 22 .andspaced from each other by insulating washers 23 and by iron washers 24which serve to, eliminate cross talk between the coils. Each of thecoils 2| is ordi a ily pr vided with two windin s 25 and extend slightlybeyond the end coils.

The insulating washers 23 are fitted on each side of the coil 2|, andadjacent to each insulating washer is an iron washer '24 which providesshielding to prevent cross talk between the coils. Associated with eachcoil 2| is a terminal supporting washer 33 having insulated wires 34,35, 36 and 37 imbedded therein and extending therefrom. One end of eachof said wires is cut short to form terminal stubs'40, 4 l '42 and 43 towhich the ends of the windings 25 and 26 are connected while the otherends 44 of the "wires are relatively long so that they may be connectedto the individual Wires in a transmission cable. The terminal supportingwasher 33 is of the type described and claimedvin the copendingapplication of E. L. Drom Serial No. 717,527, Ifiled December 20, 1946.

Any desired number of such coils may be mounted on the dowel 22 afterwhich the windings on the coils are connected to their respective stubterminals on the terminal washers. The coils are held firmly on thedowel by fasteners at each end, for example,spring fastening washers 45forced over the dowel ends and againstthe iron washer adjacent to theend coils.

After the coils have been assembled on the dowel rod 22 a perforatedinsulating strip '50 made of paper or any suitable insulating material,which may be bent into a U-shape and provided with an aperture 5| to fitthe dowel end, is placed over the coils so that the perforated legs ofthe U engage the peripheral surfaces of the coils on opposite sides withthe terminal stubs 40, M, 42 and 43 extending through the perforationsand bent over to prevent possible short circuits from occurring betweenthe terminal stubs and the coil windings during handling thereof. Ihelong ends. of the wires leading from the terminal washers 33 are broughtout along the length of the loading coil assembly at both ends. All thecoil winding ends that are to be connected into one section of a cableshould be connected to conductors whose long ends 44 are brought out atone end of the loading coil assembly and the other ends of the windingsshould be connected to the conductors whose long ends 44 are at theother end of the assembly. The assembly 20 is fitted into an insulatingtube 52, for example, a cardboard or paper board tube of the typeusedasza mailing tube, which should be long enough to The con duetors 44may extend freely from both endsqof the tube. The tube covered unitafter being thus assembled may be impregnated and coated by any suitablemethod with any suitable insulating compound 53, for example, asolvent-type varnish, to protect it from adverse atmospheric conditionsand moisture, such for instance, as the compound and method ofimpregnation described in the copending application of E. J. Crane- R.P. Cross, Serial No; 717,526, filed December 20, 1946. It is preferablethat the manner of impregnation and the material used will permit theinsulating compound to penetrate into interstices between the coils andthe tube.

In another embodiment of the invention, instead of using the perforatedstrip 50 to prevent the occurrence of short circuits between theterminals and the coils, strips of tape and 55 may be laid across andadhesively attached to the peripheral surfaces of the coil, the stripsextending lengthwise of the dowel 22 and lying adjacent to the terminalstubs ii), 4!, Q2 and 43 which may be bent fiat across the top surfaceof the attached tape (Figs. 4 and 5). As in the other embodiment theentire assemblage may be encased in an insulating tube 52 after whichthe tube-covered unit may be impregnated and coated with a suitableinsulating compound 53, as heretofore described.

What is claimed is:

1. A loading coil unit comprising a preformed absorptive cardboardinsulating tube, a plurality of loading coils .disposed in consecutiveorder Within said tube, conductors connected to said loading coils, thefree ends of said conductors said tube by virtue of the absorptivequality of said tube.

2. A loading coil comprising a coil element, a terminal supportingmember adjacent to said coil element having terminals connected to saidcoil element, a strip of tape lying across said coil element andadjacent to said terminals, said terminals being bent over to engage theouter surface of said tape to prevent short circuits from occurringbetween said coil element and said terminals, a preformed tube made ofinsulating material and of substantially the same inside diameter as theoutside diameter of said coil element disposed around said coil elementand terminal supporting member, and a coating of insulating compoundsurrounding the tube-encased assembly.

3. A loading coil unit comprising a plurality of loading coils havingshort extending terminals, said coils being grouped together in a singlerow, a strip of tape lying across said coils and adjacent to saidterminals, the terminals being bent over the top surface of the tape toprevent short circuits between the coils and the terminals, a tube "madeof absorptive insulating material disposed around the aforesaidassemblage, the said conductors extending out of the ends of the tube,and a coating of insulating compound around said tube-coveredassemblage, portions of the compound extending into interstices betweenthe coils and the tube by virtue of the absorptive quality of said tube.

4. A loading coil assembly comprising a rod, a plurality of toroidalcoils mounted on said rod, 9. terminal supporting washer associated witheach coil having terminals connected to said coils and having leadsextending therefrom, a strip of as isgos tape lying across said coilsand adjacent to said terminals and said terminals being bent over thetape to prevent short circuits from occurring between the coils and theterminals, a preformed tube made of insulating material and ofsubstantially the same inside diameter as the outside diameter of saidcoils and washers surrounding said assemblage of coils and washers, anda coating of insulating compound around the tubecovered assemblage.

5. A loading coil assembly comprising a plurality of torodial coilshaving central annular openings, a supporting rod extending through saidopenings, a terminal supporting washer associated with each of saidcoils, said washers being mounted on said rod, terminal carried bv saidwashers and connected to said coils, a strip of tape lying across saidcoils and adjacent to said terminals and said terminals being bent overthe tape to prevent short circuits from occurring between the coils andthe terminals, an absorptive insulating tube surrounding said assembly,and a coating of insulating compound on said tube-covered assembly.

6. A loading coil assembly comprising a supporting member, a pluralityof toroidal coils mounted on said supporting member, a terminalsupporting washer associated with each coil having terminals connectedto said coils and leads extending therefrom, a strip of tape on saidcoils and under said terminals to prevent possible short circuitsbetween said terminals and said coils, an insulating tube ofsubstantially the same inside diameter as the outside diameter of thecoils and the washers disposed around said assemblage of coils andwashers, and a coating of insulating compound around said tube-coveredassemblage.

7. A loading coil assembly comprising a supporting rod, a plurality ofcoil elements mounted on said supporting rod, supporting membersassociated with said coil elements and having terminals connected tosaid coil element, a strip of tape laid longitudinally of the rod acrosssaid coils and underneath said terminals to prevent short circuitsbetween said terminals and said coils, a tube made of insulatingmaterial disposed around said assemblage of coils and terminal members,and a coating around said tube-covered assemblage.

8. In a loading coil unit as claimed in claim 1, terminal supportingwashers associated with each of said loading coils, said washers havingsaid conductors extending therefrom and also having terminals connectedto said loading coils thereby to effect connection of said conductors tosaid loading coils, and a perforated insulating strip disposed on saidcoils with said terminals extending. through the perforations in saidstrip.

9. In a loading coil unit as claimed in claim 1, a rod for supportingsaid loading coils, individual terminal supporting members associatedwith said coils having terminals connected to said coils and having saidconductors extending therefrom thereby connecting said conductors tosaid loading coils, and a perforated insulating strip laid across saidcoils with said terminals extending through the perforations.

10. In a loading coil unit as claimed in claim 1, wherein said loadingcoils are toroidal in form and have central annular openings, asupporting rod extending through said openings, terminal supportingwashers associated with each of said coils, said washers being mountedon said rod,

terminals carried by said Washers and connected REFERENCES CITED to saidcoils, said conductors also being carried The muowing references are ofrecord in the by said Washers whereby said terminals effect file of thismytent. connection of said conductors to said loading 6011s, andaperforated insulating sheetlaid across 5 UNITED STATES PATENTS said.00115 with said terminals extending through Number Name Date theperforations. 1,148,792 Olsson Aug. 3, 1915 1,231,516 Fondiller June 26,1917 WILLIAM DROBISH- 2,047,731 Greemidge July 14, 1936 EDWIN DROM- 102,079,697 Ranges May 11, 1937 2,234,576 Ranges Mar. 11, 1941

